The Olympus 14-150 f4-5.6 10x zoom does most things pretty well onall m4/3 cameras I've used it on, especially on the now old E-P3. Here, on the GX7, I took it to the races for the day to see how it coped with moving subjects. I used the electronic shutter because the readout from the sensor is about 10ms. This can cause things to slant if your panning or your jusject is moving across the frame.
I did experience this but it doesn't really spoil the image as a whole. One instance where it could cause concern is with moving vehicles, where the tyres become oval shaped. Just be careful, that's all.